Final answer:
Sentence 18 can be revised using the imperative mood by choosing option b, which is 'Give me something more convincing than that.'
Step-by-step explanation:
Sentence 18 can be revised using the imperative mood by choosing option b, which is "Give me something more convincing than that." The imperative mood is used to give a command or make a request, which is exactly what the speaker is doing in this sentence. By using the imperative mood, the speaker is asking for a more convincing argument from the author.